Computational models utilized in optimal proximity correction (OPC) processes include parameters which are either determined empirically or are otherwise provided by optical equipment manufacturers for the optical equipment utilized in lithography processes. For example, optical equipment manufacturers typically provide for the benefit of nano circuit designers optical equipment parameters such as lens aberrations, flare, numerical aperture and illumination pupil or beam intensity profile. In short then, the parameters provided by the optical equipment manufacturer are not measured nor verified prior to a computational model for OPC being calibrated.
Unless any given computational model parameter is measured and verified, certain inaccuracies may result in the computational model. Therefore it would be highly desirable to have a new and improved method of measuring and verifying illumination pupil for lithography exposure equipment.